3.26 GA BLACK SMOKER-TYPE MINERALIZATION IN THE STRELLEY BELT, PILBARA-CRATON, WESTERN-AUSTRALIA

Early Archaean (3.26 Ga) volcanogenic massive sulphide (VMS) deposits located within the low strain and very-low metamorphic grade Strelley greenstone belt, East Pilbara, Western Australia, contain exceptionall y well-preserved sulphide textures which are directly analogous to tho se formed in black smoker chimneys at present-day submarine hydrotherm al vents. The VMS deposits are associated with seafloor alteration zon es in and below silica-carbonate laminites, at the top of a pile of th oleiitic to calc alkaline intermediate and element abundances indicati ve processes. VMS mineralization comprises Zn-rich sulphide lenses wit h significant Cu and barite, and variable Ph and Ag, above Cu-rich str inger zones, all of which are similar to Phanerozoic VMS deposits. Sul phide-sulphate mineralization implicates hydrothermal discharge into s ulphate-bearing ocean waters.